Wireless LAN products available on the market include dual-mode-compatible products having both an access point (AP) function and a station (STA) function.
Further, functions for the purpose of enhancing security and for utilizing wireless bandwidth effectively have also been provided. For example, the specification of Japanese Patent Laid-Open No. 2006-101416 provides a communication scheme for connecting to a first network, sending and receiving information relating to the construction of a new second network within the first network and shifting to the second network in order to execute an application.
However, with this example of the prior art, a problem which arises is that if a station participating in the second network leaves the network, other stations in the second network cannot return to the first network.
FIG. 22 is a sequence diagram useful in describing this problem that arises in the conventional network communication control method. In this example, a personal computer (PC) 101, display 102, printer 103 and digital video camera 104 are connected to an access point (AP) 100 and form a home network. Under these conditions, the digital video camera 104 requests the formation of a temporary network and the display 102 forms the temporary network by acting as an AP. Thereafter, the digital video camera 104 leaves the temporary network.
First, the digital video camera 104 sends the printer 103 a network transition request via the AP 100 (S2200). In response to this network transition request, the printer 103 issues a network transition response (S2201). Similarly, the digital video camera 104 sends the display 102 a network transition request via the AP 100 (S2202), and the display 102 issues a network transition response (S2203).
Next, the display 102 ceases operating in the STA mode (S2204) and operates in the AP mode (S2205). The display 102 then transmits a beacon signal (not shown) periodically. When the display 102 operates in the AP mode, the camera 104 and printer 103 each execute processing to connect to the display 102 (S2206 to S2209) and form a temporary network. By virtue of the temporary network, the camera 104 displays a streaming image on the display 102 and prints to the printer 103.
Subsequently, if the user of the camera 104 cuts off power to the camera or if communication quality deteriorates, communication between the camera 104 and display 102 is interrupted (S2210). Since the display 102 is operating as an AP in this case, it detects that the camera 104 has left the temporary network.
However, the connection between the display 102 and printer 103 is maintained. As a result, the display 102 and printer 103 are left in a state in which they are not being used by anyone and cannot return to the home network.
Accordingly, the personal computer 101 cannot access the display 102 and printer 103 via the AP 100 of the home network (S2211, S2212, S2213).
Thus, as described above, a problem with the conventional communication control method is that the system is not user friendly as far as devices connected to the home network are concerned.